The 'new' sites offered as a transformation from groups might be easy to use for brand new users who have seen nothing else, but a pain for old sharepoint users. What I have noticed is that the new site, despite being a site collection does not appear in the list of site collections in admin center.
I see here (Missing features on new sharepoint online sites) that there is a powershell script to turn the 'new' site into an old style 'site collection'. Did someone try it and does the converted site collection finally appears in the central admin interface?